Internal-combustion engine.



L. B. HARRIS. INTERNAL COMBUSTIONENGINE.

APPLICATION FILED OCT- 30. l9l4.

Patented July 25, 1916 7 SHEETS-SHEET I.

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INTERNAL COMBUSTION ENGINE.

APPLICATION FILED OCT. 30, I9I4.

1,1 92,50. Patented July 1916.

L. B. HARRIS.

INTERNAL comusnom ENGINE.

APPLICATION FILED OCT. 30. I9I4.

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INTERNALCOMBUSTION ENGINE.

APPLICATION FILED OCT. 30. I9I4.

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Patented July 25, 1916.

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I.. B. HARRIS. INTERNAL COMBUSTION ENGINE. APPLlcATloN FILED ocT. so, 1914.

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INTERNAL COMBUSIION ENGINE.'

APPLICATION FILED OCT. 30. I9I4.

Patented July 25, 1916.

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INTERN/IL COMBUSTION ENGINE. `APPLICATION FILED OCT. 30, 1914.

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Patented July. 25, 1916.

LEONARD B. HARRIS, OF HADDON HEIGHTS, NEW JERSEY, ASSIGNOR TO HARRIS PATENTS COMPANY OF NEW YORK,'N. Y., .A CORPORATION OF DELAWARE.

Specification of Letters Patent.

Patented July 25, 1916.

Application led October 30, 1914. Serial No. 869,392.

To4 all whom t may concern Be it known that I, LEONARD B. HARRIS, a subject of the King of Great Britain, residing at Haddon Heights, in the county of `Camdenand State of New Jersey, have invented new and useful Improvementsin lnternal-'Combustion Engines, of which the following 4is a specification.

This invention relates to'an internal combustion engine and while the invention relates particularly "to an engine of the Diesel type, such as that set forth in my application Serial No. 726,045, filed Oct. 16, 1912, many features of the invention are applicable to engines of othertypes.

In one aspect, certain features of the invention may be regarded as improvements upon the invention disclosed in my application referred to above. In the invention covered by that application, the engine embodies in itsconstruction scavenging air cylinders operated in conjunction with power cylinders so that the mechanism of the engine renders the engine capable` of starting 'by means of compressed air admitted to the lair cylinder. The operating lever which started the engine on air also admitted, fuel toithe power cylinders so that after the engine was started on air, its operation continued automatically on fuel. The; arrangement was such that the air was cut off from the air cylinders as soon as the fuel kwas turned into the power cylinders. ln other words, when the engine had been started on air, the driving of the engine with fuel began as soon as the driving by compressed air had ceased.

One of the objects of the present invention is to provide an engine of -this class with a construction which will operate uin such a way that the driving ofthe engine by means of compressed air maybecontinued after the power cylinders are operating with the fuel, the general purpose being to enable the engine to gather speed and'power quickly.

A further object of the invention is to provide an arrangement whereby the control of the operation of the air cylinders, when desired, may be rendered independent of the operation' of the'power cylinders,v

the general purpose being to enable the engine when desired, to be driven as an airv motor by means of compressed air alone.

A vfurther object of the invention is to provide improved means for'controllingthe relation of the air cylinders and the power cylinders, including improved valve means operating with small clearance losses and enabling the air cylinders to operate' as scavenging cylinders for the power cylinders.

Further objects of the invention will 'appeai more fully hereinafter.

The invention consists in the general combination of parts and simplicity of details hereinafterdescri'bed, all of `which contribute to produce an eiiicient internal combustion engine.

The preferred embodiment of myv invention will be particularly described in the following specification while the broad scope of my invention will' be pointed out in the appended claims. v

The invention also consists in the method described hereinafter.

In the drawings: Figure 1 isa perspective partly broken away and illustrating an engine v embodying my invention. Fig'. 2

e5 fr is a vertical section taken through the cyl- Y inders-of the engine and further illustrating the preferred arrangement of the parts. Fig. 3 is a front elevation of a control device which constitutes a feature of the ,invention, certain parts being broken away. Fig. 4: is a vertical section through the control device taken about on the line 4-4 of Fig. 3. Fig. 4 is a vertical cross section I through the valve chest .shown in Fig. 4, taken about on the line -Ll of Fig. 4. Fig. 5 is a front elevation and partial section further illustrating the preferred ar- `.rangement of the control device illustrated v section takenfcir the line y'iL-7 of Fig. 6. Fig.- 8 is a detail partially in section illustrating a lost motion device for preventing the feeding cfvfuelto the lpower cylinders until the .engine has been started on compressed air. Fig. 9 is avertical section taken through the valve lwhich controls the comniunication between the cylindersI and'between the cylinders and the air manifold,

which holds the air for scavenging the power cylinders. Fig. 10 is a frontelevasoA tion and partial section. showing the valve illustrated in Fig. 9 and its contiguous parts. Fig. 11 is a vertical sectionshowing a valve of rotary type which I may use to perform the function of the valve illustrated inFigs.

9 and 10. Fig. l2 is a vertical section taken near the plane of the section Fig. 11 and further illustrating the valve.r Fig. 13 is an elevation partially in section and broken away, further illustrating the valve arrangement when the valve is of the rotary type. Fig. 14 is a view showing the figure which will appear upon an indicator card if taken from the scavenging cylinder when starting the engine on compressed air. Fig. 15 is the card of the air cylinder produced during the first revolution. Fig. 16 is the cardfproduced on the second revolution, and each succeeding revolution while running-on compressed air. Fig. 17 is the card which is produced by the scavenging cylinder operating simply as a scavenging cylinder. Fig. 18 is a compression card taken from the power cylinder while the engine is being started byV air and before oil is admitted into the power cylinder. y y

The pressures shown on the cards are only approXimate.

Before proceeding to a detail description of the invention, it will facilitate the disclosure of the invention to state that in the embodiment of the invention'described, they cylinder arrangement involves they use of air cylinders preferably arranged in tandem with the power cylinders, and the-arrangement for starting the engine is extremely simple. A hand operated member is provided, the rst movement of which operates to admit compressed air to the air cylinders to start the engine with compressed air. If .the movement of the hand Aoperated part, such as a hand wheel, is further continued in the same direction, fuel will be admitted to the power cylinder or cylinders and the engine will be driven by means of fuel and compressed air. If the movement of ther hand operated member is continued still further, the driving of the engineoncompressed air will be discontinued automatically and the engine will then run regularly on fuel as its motive power.

The engine may comprise as many cylinders as desired. In the accompanying drawing, I have illustrated in detail only one power cylinder and its corres onding scavenging cylinder, this being su cient to illustrate the preferred construction of the engine as to the cylinders.

Referring more particularly to the parts, y20- represents the engine frame or base, which may be of any suitable form carrying a crank shaft 21 to which the connecting rods 22 of the engine attach. The connecting rods 22 attach to wrist pins 23 each of which is carried upon a trunk piston 24 intercepting valve 39.

.which communicates through a passage' 32 and ports 33 `with the cylinder 27 for the admission of scavenging air which passes across the upper face ofthe piston 26 and carries the gases of combustion out through the ports 28. -The air cylinders 25have air ports 34 the communication of which with the ports 32 and the air manifold 31 is con-y trolled by valve means 35 which includes the This intercepting valve is preferably/fluid controlled that is, automatically by the admission of a fluid such as air. The preferred construction of the intercepting valve is yillustrated in Figs. 9 and l0; each intercepting valve preferably comprises a housing 36 in which there is rigidly mounted tubular bushings 37 L and 37h, the bushing or cage 37b being formed with a seat 38 for a movable piston valve 39 which is adapted to move up or down in the bushings. 'lhe bushing or cage 37b is provided with ports 40 communicating with a chest 41, which chest communicates with the port 34. The lower portion of the valve 39 hasa reduced neck 42 whereby an annular circumferential passage 43 is formed.

I prefer to provide mechanical driving mechanism driven by a moving part of the .engine for actuating the .admission valves periodically at the proper .times to admit air to the intercepting valve 39 and through the coperation of which this air is admitted to the air cylinders or scavenging cylinders in driving the engine on compressed air, as later clearly described. When the engine is at rest or running on fuel, however, the admission valves are not in cooperative relation with the mechanical driving mechanism. I prefer to bring the valves and the mechanical driving mechanism into coperative relation by fluid operated means preferably pneumatic means. I accomplish this in a very simple manner by means ofthe air pipes or conduits 46 and 50.

When theengine is to be reversible, I provide two admission and cut-off valves 44 for admitting and cutting off air to the intercepting valves. These valves are preferably fluid controlled and are preferably located one on each side of the intercepting valve; and are duplicates of each other in construction; there are two such valves, one corresponding to each direction for the engine,

tain direction of drive for the engine, when thc engine is at rest is on its seat 54 closing the inlet 54, but when the air is turned on in pipe 46, this valve is blown across the air chest 54 against the seat 45. The seat 45 is preferably formed in the lower end of a bushing 47 which has a tubular head forming the outlet from the air chest with ports 48 communicating with a passage 49 which communicates with the aforesaid annular passage 43. It is understood that when the engine is to be driven by compressed air in one direction, compressed air is admitted in the pipe 46 for example. but not in the pipe 50, and vice versa. 'hen the valve 44 is raised to its seat 45 by the admission of the air,'a. roller 51 carried by the upper end of the stem 52 is in a position to be engaged by a mechanically operated member such as cam 53 on the cam shaft 35', said cam shaft extending longitudinally of the engine and being driven through a ysubstantially vertical shaft 55 and gearing 55a fronrthe main shaft 21 of the engine in some such man-ner as that illustrated in Fig. 1. When air .is not turned on in the pipe 46, the valve 44 rests upon its lower seat 54.A It is understood also that the intercepting valve 39 is normally in its extreme low position in which it is illustrated in Fig. 2.`

The space between the'bushings 37 and 37b forms an annular port 56 with which the port 49 communicates. On the front side this port 56 communicates with a pipe 57 which conducts the air down into a small air cylinder 58 or pilot cylinder in which moves a piston 59 having a. stem 6() connected with the valve 39; the upper valve bushing37b is provided with a cross bar or bridge 61 against which seats a spring 62 the lower end of which seats over a boss 63 at the lower end of the valve 39 and this spring is compressed by the upward movement which is imparted to the valve by the compressed air in the pilot cylinder 58. Then the valve 39 is forced upwardly so that its upper end 64 comes against the seat 38,

communication is cut off between the port 34 and' the manifold 31; but through the annular port 43 com unication is maintained with the air pipe 57 so that the air pressure in the pilot cylinder 58 is maintained and the valve held on its upper seat.

1n the bridge 61 there is mounted a. stem 65 which extends upwardly and which carries a guard 66; under this guard 66 there is mounted a spring 67 the lower end of which thrusts against a disk valve 68 which normally closes the upper end of the valve bushing 37". Tn order to cushion the upward movement of the piston 59, the upper end of the cylinder 58 is provided with a stop-cock 69. When the stop-cock is open, the air is driven out and by partially closing the stop-cock, the exit of the air is choked and a cushioning effect results. A similar cushioning effect is brought about when the valve 39 is forced back by spring 62 to its lowest position. For this purpose, I prefer to provide the lower bushing 37L with a bleeder screw 70 having a cut in its side which opens the lower end of the case to the atmosphere. By adjusting the screw 70 of course, the amount of opening can be regulated to control the cushioning effect. An air space 71 is formed over each valve 68 and these air spaces 71 are in communication with the air manifold 31 and the scavenging ports 32.

The engine as stated, is preferably of the Diesel type, each of the heads 72CL of the power cylinders 27 being provided lwith `fuel admission means preferably in the form of an atomizer 72 which opens mechanically at the proper times through 4the operation of mechanism 73 disclosed in detail in my former application Ser. No. 726,045. This mechanism 73 is preferably operated partly from the aforesaid cam shaft 35 and partly from the control device 121 to be disclosed hereinafter and which controls the admission of air to the'pipes 46 and 50. This mechanism 73 preferably comprises rockers or actuators for the valves or atomizers 72 which are periodically rocked by cams 75 on 'the aforesaid camshaft 35. Each atomizer 72 has a stem 75 which rides upon two levers 7 7 fulcrumed at 7 8, the outer ends of the levers being connected with actuated stems 79. These levers arearranged so that neither lever prevents the opening of the atomizer by the other. This atomizer is set forth clearly in my application Serial No. 769,925. The lower ends of these stems are provided with rollers 8() resting on the upper surface of the corresponding rockers 74. The rockers 74 rock about the pivot pins 81 and are held. by springs 82 on their cams 75. The actuating stems 79 slide freely through swiveled guides 83, each of said guides having. a swivel connection with a crank arm 84; and each of these crank arms S4 is rigid with the adjacent arm 85 connected by the link 86 with a slide 87. These slides are pulled down by the bell cranks 89 and pulled up by' the springs. 87a and guided by guides 87" (Fig. 2). The position of these slides 87 determines the positions of the crank arms 84 and also the point where the rollers will lie on the rockers 74; this evidently determines the amount of movement of the levers 77 and the atomizer stems 76. lThe levers 77 are pulled down by any suitable means such as the springs 88 attached to them. The slides 87 are controlled by a T-arm 89 having its pivot at 90 and there is one of these T-arms 89 corresponding to each power cylinder; and the different T-arms 89 are connected together by a link 91 which in turn is controlled by my control device 121 about tobe described. The atomizer stems 76 are held closed and down on their levers7 7 by springs 76a. The lower end of each stem has a conical point forming a valve for the atomizer. When the stem is raised, a charge of fuel and air pass into the power cylinder through openings 7 6e. In other words, each atomizer is valved, or valve controlled. In connection with the pumping mechanism, I prefer to provide variable means for varying the amount of fuel delivered by the, pumps.

The fuel for thepower cylindersis supplied to them individually through pipes 92?* and 92b from pumping mechanism 92, a preferred form of which is disclosed in detail in my eo-pending application Serial No. 768,484led May 19, 1913(y This pumping mechanism 92 preferably comprises a numvber of pumps 93 the plungers 94 of which are each connected by an oscillating block and sliding connection 95 with the arm 96 of a rocker 97 having its fulcrum at 98. Each rocker 97 has an arm 99 and these arms are disposed on opposite sides of a cam or eccentric, 100, said cam or eccentric being fixed on a cam shaft 101 which is driven from the'vertical shaft 55 by suitable gearing 102. A variable adjustment is provided for the fulcrum pins 98 enabling them to be f controlled by the governor 109 of the engine and also by my control device. For this purpose, the fulcrum pins 98 of the rockers 97 arecarriedon slides 103 mounted to slide horizontally, and on each pin 98 there is loosely attached a double worm sector. 104;` the upper teeth of these sectors engage worms 105 on the same lshaft 106, said.y woins having right and left hand threads so that for a certain direction of rotation of the shaft 106 the fulcrum pins 98 will be adjusted toward each other or away from each other. Theflower teeth of the double sectors 104mesh with similar worms 107 carried yon a shaft 108. By rotating the shaft 108, the sectors mayl be rotated so as to adjust the pins 98 toward or away from each other. l When one pair of worms is adjusting the sectors, the teeth at the opposite end of the sectors roll on the other worms as though they were racks. The worm shaft 106 is controlled bythe governor 109 of the engine by means of a lever 10 which lever is connected by a link 111 with a rack 112 meshing with a pinion 113 .on the shaft 106.

Compressed air is brought from 'a reservoir to the atomizer of .each cylinder by a pipe such as 'pipe 76d; and the compressed n air reservoirv (not illustrated) is supplied with compressed air by a compressor 76"' driven in any suitable manner from shaft 21.

A pipe 7 6c leads from the air compressor to the air reservoir. The governor 109 may be of any suitable construction. The fuel for the pumps may be supplied from a suitable reservoir 114 having a pipe 115 connecting with the inlet pipes 116 for the pumps. The cam 100, as it turns around, will strikefirst one of the arms 99 and then the other, and in this way operate the pump plungers alternately; any number of cams or eccentrics 100 can be attached on the shaft 101 corresponding to the number of levers 99 and pumps 93'and power cylinders 27. There is also a pair of pumps to correspond ivith every pair of cylinders. The amount of stroke of the pumps will depend upon the position of the fulcrum pins 98 which will evidently give a range from zero or no stroke to the maximum possible stroke.

Under the influence of the governor, the fulcrum pins 98 may be moved so far apart that the pumps will have no stroke, and this will cut off the fuel supply. The worm shaft 108-is controlled from my control apparatus by means of a pinion 11,7 on the shaft 108 which meshes with the rack 118 connected with my control apparatus. This rack simply lies onvthe pinion, and the outer end o'f the rack has a handle 119 which enables the rack to be raised when desired to disconnect it from the pinion. At thistime, the shaft may be rotated directly by means of its attached hand wheel 120. This enables the several positions of theworms 107 to be' altered when desired.

I shall now proceed to describe my controldevice and its relation to the other mechanism and particularly its relation to the intercepting valve. With my control device 121, there is preferably an air chest or valve 'box 122 the preferred construction of which was disclosed in my former application Serial No. 726,045. As illustrated in Figs. 4 and 4a, this air chest is supplied from'-` a suitable source with air under pressure by a supply pipe 123 which may let theairjinto j either of two ports 125 from which i-t 'is normally closed off by two throttle valves 124, pressed toward their seats by springs 124a and the pressure in the air chest 122.

If one of these valves 124 Ais opened, commu nication is` established from the interior of the chest 122 and its corresponding port 125 which connects with the aforesaid pipe 46.

'When the other valve 124 is opent the air `is let in to the pipe 50. In order to raise either of these valves 124, as may be desired, each valve has a downwardly extending stem 126 and these stems have outwardly Vprojecting vdogs 127 which pass through slots 127 and rest upon toes 128 of ra rocker 129. The spindle of this rocker carriesy a rigid arm 130 and this armhas a pin and slot connection 131 with the lower end of a rack 132, said rack having teeth in `mesh with the segment 133. This segment may be rotated by an air controlling member preferably in the form of a lever 134. I provide an arrangement for enabling this lever 134 to be moved independently of the hand -wheel 148. For this purpose, the spindle 135 of this segment preferably has a flat extension which is received in a slot 136 formed in the lever 124, said flat extension being held normally at the upper end of the slot by a removable pin 137. The case of the air chest 122 is'provided with a quadrant 138 which is provided at any suitable point with means such as the notch 139 for indicating the neutral point of the lever. The lever 134 has a spring pressed pin 140 which engages the notch when the lever is in its vertical or neutral position. In order to move this lever 134 to admit air automatically to the air cylinders to start the engine when the controlling member or wheel is moved, I prefer to provide an actuator 141 which is preferably in the form of a slide mounted to slide horizontally in the guide 142. This actuator is preferably formed with a central slot in the opposite ends of which engaging means such as dogs 143 are mounted to move on pivot pins 144, said dogs being spring pressed, for which purpose they are preferably connected by a spring 145 which tends to force theminwa rdly` through the slot. The dogs are preferably provided with laterally projecting lips 146 on their upper sides which engage the upper edge of the slots and limit the inward movement of the dogs.

When the lever 134 is in its neutral or normal position and the actuator 141 is in its normal or neutral position, the lever lies between the dogs 143 sc that if the actuator 141 is moved toward the right, the left hand dog engages the lever and moves it toward the right, and vice versa. Movement in one direction will open one of the valves 124 and movement in the other direction'will open the other valve 124. The upper sides of the dogs `near the plane of engagement y with the lever 134 are formed with curved faces 147, (see Fig. 6). These faces are cut away in this manner so that after the actuator comes to a predeterminedv point, the lever will be released from the dog which has been moving it. The lever will then return to its normaI or neutral position tirough the action of a spring 148 which is provide a. hand operated member such as a hand wheel 148, said hand wheel being attached to a spindle 148a carrying a worm 149', said worm meshing with the worm wheel 150. This worm wheel has a pin and slot connection with theactuator, for which purpose it carries on its inner face a block 151 pivoted on a pin' 15P, and thisI `block slides freely in a vertical slot 152 which is formed between two horns 153 which extend down from the actuator. From an inspection of Fig. 5, it will be evident that if this worin wheel 150 is rotated toward the right, its spindle 154 will rotate toward the right, the block 151 will also swing toward the right, so as to displace the actuator 141 toward the right, and at the same time, the block will move slightly downwardly in the slot 152. The spindle 154 has an arm 155 which extends downwardly from it and to this arm attaches the link 91 which controls the T-arms 89 which in turn control the operation of the atomizer stems 76. rIihis arm 155 is not rigidly attached .A to the spindle 154, but is preferably attached to the spindle through the medium of a lost motion device preferably comprising a 'bushing 156 rigid with the arm having a circumferential slot 157 infwhich moves a key 158 carried by4 the spindle; from an inspection of Fig. 8, it will be evident that if the spindle is rotated in either direction, it will not affect the arm in any way, until the key 158' engages the bushing. This arrangement allows a suliicient movement of the spindle to run the engine on air, and on air and oil before the air is cut off. The inner end ofthe s indle 154 is rotatably mounted in the bracket 159 and beyond this bracket an upwardly extending arm 160 is attached, which arm is connected with the link 161 which extends downwardly, and the, lower end of this link is attached to an arm 162 of a `bell crank lever 163, the opposite arm 164 thereof has an adjusting pin and slot connection 165 with the aforesaid link 118 the outer end of which isformed with? rack teeth 167 which engage with the aforesaid p'inion 117.

A bushing similar to the bushing 156, which is illustrated in Fig. 8, is fitted into .the hub of arm 160 and is attached rigidly is called to the fact that when the parts are in their neutral position, the link 160 is on its upper dead center so `that whatever be the direction of rotation of the hand wheel 148 to start the engine, the same'direction of movement will be given to the bell crank lever`163, that is, in either direction of driving the engine, the arm 162 will be depressed.

In order to indicate what is taking place in the control of the engine corresponding to. any given position ofthe wheel 148', I prefer to provide a dial 168 coperating with which there is provided av pointer 169 power cylinders, and beyond the line 171 the s engine will be driven on fuel only. All of which is indicated by the dial. In using the term oil, it is understood, of course, that I do not wish to be limited to oil fuel, but

simply use this term to indicate a fuel.

Though it is not necessary to start the engine, I prefer to provide a hand operated vISIS leases the lever 134, one of these buffers 174` cam 172 which is disposed between the' arms 99 of the pump as indicated in Fig. 1, and this cam can be rotated or oscillated by means of a suitable crank 173 to operate the pumps by hand.

Arrangement is made for disconnecting the lever 134, Fig. 6a, from the actuator in order to enable the engine to be run continuously by air alone, and without moving the yhand wheel 148 by means of ywhich the yengine is ordinarily started. For this purpose, the aforesaid slot 136 is provided. By

referring to Fig. 6, it will be seen that by removing the pin 137 the lever 134 can be pulled up, extending the spring 148; the pin 137 is first removed and then replaced in the lever above the spindle, as shown in Fig. 6. When the lever is in this position, its lower end is lifted high enough to clear the dogs 143 so that the'lever can be operated freely and independently of the actuator 141.

It is evident that the wheel 148 constitutes means for controlling the admission of fuel charges to the power cylinders, and through the medium of the lever 134 this wheel may also control the admission of air to the scavenging cylinders. It is also evident that if desired the lever 134 can be pulled up as indicated in Fig. 6a and be operatedV by hand independently of the hand wheel 148. In other words, this lever 134 which controls the admission of vcompressed air is operable by and also independently of the hand wheel 148.

n One of the functions of the actuator 141., after the lever 134 has released itself, as illustrated in Fig. 6, is to prevent an acci# Vdental operation of the lever which would cause a flow of air in the engine to oppose direction, and for this purpose each end the actuator is provided with a projectionvor buffer 174, and the actuator is arranged so that just at the time that it reis substantially under the notch 139, so that when the lever 134v swings back to its neutral position it does not oscillate there, but

strikes and comes to rest against the buffer; furthermore, it will be evident that as long as the actuator is in this position it will be `impossible to move the handle of the lever toward the right, that is in a direction which would admit a-ir to oppose the driving direction of the engine occurring at that time. But, it is still possible to move the lever 134 to the left, admitting air in the direction that the engine would then be running; this may be done if desired to aug-- ment the power of the power cylinders by admitting compressed air to the scavenging cylinders at the same time.

In order to indicate to the operator whether the engine will go ahead or astern for a certain direction ofl rotation of the wheel 148, I prefer to provide the spindley 148a of the hand wheel 148 with a screwu illustrated in Figs. 9 yand 10, I may employr a valve of rotary type such as that illustrated in Figs. 11 to 13, and when using this type of valve, I prefer to place both the inlet valves on the same side of the intercepting valve. These valves are Very etlicient in operation on account of their small clearance spaces. The preferred form of this type of valve comprises a valve casing 181 in' 'the upper portion-of'which one or more valves 182 are provided, through which air is admitted lto the manifold 183. Immediately under these valves 182, I provide a rotary valve 184 having a port 185. lVhen the valve is in the open position, this port 185 opens communication from passage 186 from the air cylinder so that air can pass into the air space 187 over the rotary valve and up through the valves 182. The air space 188 over the valve 182 connects the manifold 183 with the scavenging port 189` to which air is admitted to each power cylinder. At the right'of the casing 181, as

illustrated, two inlet or cut off valves 1 9() are provided which are similar in construction to the inlet valve 44 already described, said valves having stems 191 which extend upwardly and carry rollers which may engage either' of two cams 192 on a cam shaft 193. Suppose the air is turned on in the pipe 194, instead of the pipe 195; this will raise the corresponding valve '190 onto its upper seat 196 and put the upper end of the same into position to be engaged by its Lcorresponding cam 192. vlVhen the cam depresses the valve, air passes through a port 197 into the lower end of a. pilot cylinder 198 and forces upwardly a piston 199 mounted in this pilot cylinder. A stem 200 extends downwardly from the piston and has a pin and slot connection with the arml 201 attached 'rigidly to the spindle of the valve 184 so that when the piston 199 has completed its upward movement the valve 184 will be rotated so that the port 185 will occupy the position indicated by the dotted lines, Fig. 12. Furthermore, the piston 199 will now move upwardly suliciently to open the passage 197 so that it will'communicate with the port 202 and this port connects with a pipe 203 which carries the air down to the port 204 leading into the valve 184. In the new *position of the valve, the port 185 opens communication then from the port 204 to the port 186 which admits air into the air cylinder and at the same time intercepts the passage of air into the chamber 187. The piston 199 is preferably mounted in a suitable liner 205 and is pressed downwardly toward its normally low position by means of a spring 206; Fig. 11 illustrates the piston in its lowest position. In order to regulate the cushioning eiiect on thepiston 199 the cylinder liner 205 is provided with a bleeder passage 205a similar to that shown at in Fig. 10. In the details of their construction, the valves 190 are similar to the valve 44 already described, and they operate in substantially the same way, that is, when the air is turned off in either pipe, the corresponding valve 190 rests on its lower seat 207. It is understood that the admission of air in one of the pipes moves its corresponding valve to its upper seat, while the air which passes into the air space 208 between the valve seats holds the corresponding inactive valve on its lower seat. The cams 192 are arranged in relative position to the cranks of the engine so that one will admit air at the correct time to turn the engine over ahead and the other, in such aposition that it will admit air at the right moment to turn the engine over astern. A suitable water circulating system is provided including a connection 30a between the water jacket 30 of the exhaust and the water chamber 72b of the head; and a pipe 30b connects with a water jacket 30 of the cylinder 27.

Suppose that it is desiredto start the engine in the regular way; turning the hand wheel 148 will rotate 'the worm 149 and impart corresponding rotation to the worm wheel 150. This will move the block 151 which slides in the slot 152 and this will cause a sliding movement of the slide or actuator 141. Suppose that this movement is in a right hand direction so as to displace the actuator toward the right, as indicated in Fig. 6; as this movement takes place, the lower end of the lever 134 is engaged by the left hand dog 143 and the lever is moved toward the right. This first movement of the hand wheel, while it rotates the Worm wheel 150 and the spindle 154 of the worm wheel, it will not impart any movement to the link 91 which controls the opening of the atomizers.. This mode of operation occurs on account of the lost motion device illustrated in Fig. 8. The movement of the lever 134 however,.operates to rotate the segment 133 and this depresses the lever 130 and rocks the toe cam 129 so that the right hand stem 126 of the right hand valve 124, as viewed in Fig. 4, is raised. This admits compressed air to the pipe 46. Then the air is admitted to the pipe 46, it raises the valve 44, as illustrated in Fig. 10, oil its seat 54 and shoves it against its upper seat 45. This prevents any further passage of the air toward the cylinder; however, if it should v happen that the cam 53 is in a position to prevent the valve 44 closing against its upper seat, air would be at once admitted past the valve 44. This will start the engine, and thereafter the cam 53 will depress the valve 44 periodically and at the proper moments to keep the engine running.

It is understood that before the air is admitted the intercepting valve 39 is down in its lowest position, as indicated in Fig. 2. When the air passes the valve 44, it goes through port 49 and into the annular port 56, through pipe 57 into the lower end of fhe pilot cylinder 58, and acts on the piston 59 and forces the intercepting valve 39 to its uppermost position. This brings the upper end of the intercepting valve against the seat 64 and cuts off communication from the port 34 into the port 32, Fig. 2, and the space 71 and manifold 31. Furthermore, the moving of the valve ,39 to its uppermost position to open communication from the annular port 56 to the passage 34 and this admits starting air into the air cylinder 25, Fig. 2. This drives the `piston 24 downwardly and starts the engine. After piston 24 has moved down to about two thirds of its stroke, the cam 53 lets the stem 52 of the valve 44 move up and the air owing against the valve from the pipe 46 immediately closes the further passage of air into the ports 49, 56 and pipe 57 and cylinder 5S. This corresponds to the point of cut off for admitting air to the air cylinder, and after this the air in the cylinder expands and cylinder 25, port 34, passages 43, 56, pipe 57, cylinder 58 to substantially atmospheric pressure thereby allowing the spring 62 to force down the intercepting valve 39 to` its lowest or normal position, see Fig. 2, and restoring communication between ports 34 and chamber 71 and manifold 31, before compression begins on the scavenging stroke. On the upstroke of the piston, the air which remains in the cylinder is slightly compressed above the port| 25a and when this pressure is raised sufiiciently, it will lift the valve 68 and air will liow into the space 71 and into the air manifold 31. This will maintain' the proper air pressure in the manifold 31 which holds th`e scavenging air for the adjacent power cylinder 27. In this way, the engine is started on air alone and it will continue to run on air alone until the rpointer 169 reaches the line 170, which corresponds to the amount of lost movement at the slot 157, as illustrated in 'Fig 8, and when the pointer reaches this line 170, the link 91 receives a movement in the proper direction. This will move the corresponding arm 84 outwardly over its corresponding rocker lever 74 and the corresponding atomizer lever 7 7 will begin to operate. The engine then operates on fuel and compressed air. At each up-stroke of the air piston 24 a cylinder full of scavenging air will be compressed and forced at low pressure into the air manifold 31. On each down-stroke the air cylinder and the intercepting valve operate as described above, until air starting air is cut off: When the upper face yof the power piston 26 passes the ports 32 and 28, scavenging air blows across the upper face of the power piston and carries the exhaust gasesv out to the exhaust manifolds 29. The scavenging air left in the power cylinder is compressed on the 11p-stroke.

When the engine is running on fuel alone on each out-stroke free air is drawn in through ports 25g, inlet valve 25, and inlet passage 25f, to fill the cylinder 25, and on the return or inward stroke this cylinder full of free air is forced into the air manifold 31 at low pressure. Hence it is seen that the scavenging piston performs its same scavenging function whether running on fuel or being air started, and performs that function in the same way, that is 1n` either case the cylinder full of air which is `at atmospheric pressure at the commencemovement of the hand wheel 148 in the same direction will increase the amount of opening of the atomizers and also will increase the stroke of the pump plungers 94. In this connection, it is understood that when the atomizers are put into operation the pumping mechanism 92 also is brought into operation to pump the fuel to the atomizers. Though, obviously, if desired, the pumps could be started before the atomizers began to operate. The last part of the movement of the hand wheel 148 however, will not have the effect of substantially increasing the movement of theactuator 141 toward the right for the reason that at this point of the movement the block 151 is on the eX- treme right and moving nearly vertically down in the lower end of the slot, and the vhorizontal component of its movement by the worm wheel 150 is very small. On this account, the lever 134 will not be moved by the buffer so as to turn the air on. However, if it is desired to turn the air on at any time into the air cylinder to increase the power of theengine, this can be accomplished by moving the lever 134 by hand toward the position in which it is shown in Fig. 6. It is understood that a movement of thelever in the wrong direction at this time is impossible on account of the buffer 174 being in the path of movement of the lever, which would obstruct such a backward movement. The pumps are brought into operation automatically when the pointer 169 arrives at the dial line 170, through the operation of the link 161 (see Figs. 3 and 4) and the rack 118 which rotates the pinion 117 in the properdirection. This produces a rotation of the worms 107 causing the arms 99 to approach each other and bring.- ing them into the range of the cam 100 which isv continuously .driven on the shaft 101. The governor 109 also `controls the position of the levers 499 by rotating the worm shaft 106 which causes a rotation of the sectors so that they approach or recede from each other according to whether more or less power is needed. The backs of the dogs 143 have inclined faces 143a which enable the lever 134 to collapse or displace the dogs when the member 141 returns to its normal or neutral position; as the spring 145 holds the pawls yildingly, it pulls thedisplaced dog back into place, (see Fig. 7).

The functions taking place in starting the engine are indicated by Figs. 14 to 18 inclusive. Fig. 14 represents the diagram which would be produced on the indicator card in starting the engine, the card being taken from a scavenging cylinder and representing several cycles which take place in starting the engine. This diagram, for the purpose of clearness, has been separated into three distinct cards or diagrams which represent the different cycles or different phases of the performance of the engine.

In the card shown in Fig. 15, a represents the initial inlet pressure line of the coinpressed air in iowing into the cylinder on the out-stroke of the piston. Although this line gives the impression that the air iscut off and used simply eXpansively, as a matter of fact, the engine starts rapidly that the air cannot follow the piston and maintain the admission pressure in the cylinder, hence, there is a marked loss of pressure as the air piston moves outwardly. On the rc turn stroke, a portion of the line lies on the atmospheric line c; the air is compressed slightly, as indicated by the line b to about seven pounds per square inch, showing that in this stroke of the piston the cylinder is performing its scavenging function, that is, it is compressing air and forcing it into the air manifold. While this card shown in Fig. .15 is being taken, the card shown in Fig. 18 is produced in the adjacent power cylinder, the piston of which is diametrically opposite and moving inwardly, that is, in the direction to compress the air in thc power cylinder. In other words, when the line a is being produced on the card, Fig. 15, line a is being produced in Fig. 18, showing that the pressure gradually increases in the adjacent power cylinder. @n the outward stroke of the power piston, the line b is. produced so as to form a narrow crescentshaped lfigure, the area of which indicates the amount of heat lost in compressing the air in the power cylinder. From the lines a and it is evident that the air which is compressed in the power cylinder gives back almost the same amount of energy which was put into it during the compressing movement.

In the second and all consecutive outstrokes of the scavenging piston, until starting air is shut off, the card shown in Fig. 16 willl be produced, showing an admission pressure line a2 which indicates substantially 30 pounds per square inch, and on the return stroke, the compression line b2 indicates the compression of the air up to about 7 pounds; and during this return stroke the cylinder performs its scavenging function, the same as indicated in Figrl. As long as the engine is running on air, a card of this general character will be produced. It should be noted that in Fig. 16 line a2 represents that very much less energy is required to turn the engine over than was the case on the first outward stroke, as

shown at line a Fig. 15. rIhe reason being that the energy is being given back in the power cylinder, as shown in Fig. 18, is assisting in the creating of the compression in the adjacent power cylinder.

The card shown in Fig. 17 will be produced by the scavenging cylinder when the engine is running normally on fuel alone, as a combustion engine. In this figure, the line A, which runs on the atmospheric line, is the admission or suction line, and the line B is the compression line, showing that compression takes place up to 7 pounds which is the pressure in the air manifold.

It will be noticed that the line Z) Fig. 15, line b2 Fig. 16, and line B Fig. 17, are the same under all conditions showing that the engine performs its normal functions of compressing a charge of scavenging air whether it be air starting or running on fuel.

In the claims where I have used the term governing, it is used in the sense of controlling. In this connection it must be remembered that many engines include in their mechanism a device known as a governor, the purpose of which is to control the speed of the engine and adapt the valves of the engine to the condition of the load on the engine. For this reason the use of the word governing in engine practice may have a special meaning, namely, the controlling of the engine by a governor. I wish it understood, however, that in the claims I have used the word governing in its ordinary meaning, that is, it has thesame meaning as the word controlling, 'Ihe cycle of operations of a Diesel multiple uint engine in which is embodied my novel method, is substantially as followsr When starting the engine on compressed air, air is admitted to the scavenging cylinders alternately on the out-stroke of each piston; on the instroke of each piston, air 1s compressed in its power cylinder up to a temperature suiiicient to ignite the combustible charge which is admitted to the power cylinders in succession; on the instroke of each scavenging piston, air is discharged and held confined, and this confined air'is allowed to pass out through the power cylinders .when their pistons arrive at a predetermined point so that they carry out the gases of combustion; vthe air which is left in each power cylinder is the air which is compressed to furnish the oxygen and ignition temperature for the fuel charge. IVhen the engine is operating as an air motor, the cycle is substantially the same except that the fuel is not admitted to the power cylinders, that is, the admission openings are maintained closed, and the fuel pumps are out of operation. IVhen using the engine to recharge the air starting bottles from the scavenging cylinders such as may be done where an engine of this descriptionis used as a locomotive, assuming that the atomizers are thrown out of' action and the fuel-pumps are put out of operation in the same way that lthey would be in bringing the engine to rest, it would be understood then, that if the locomotive continues to run, or does what is commonly called coasting, the momentum of the train driving the engine would cause the pistons to` continue their inward land outward strokes. Under these lconditions, if the air starting air were admitted to the scavenging cylinders by the hand controlled lever 134, in such a way that, the air would endeavor to drive the engine in the opposite direction to which the momentum is driving it, the effect would be that the momentum of the locomotive would drive the scavenging pistons inward against this air pressure. It being understood, of course, that the point of cut-off as controlled by the cam would become the point of admission and the usual point of admission would become the point of cut-off, owing to the reverse cams admitting the air while the engine is being driven ahead. This would cause the starting air after acting against the scavenging piston to be forced back again into the starting air reservoir with the addition of a cylinder full of free air, which would have been drawn into the scavenging cylinder before the starting air was admitted. This would have the same effect of pump-- ing up the starting air bottles, at the time having a checking effect on the momentum of the locomotiv f It is obvious that the above description sets forth anovel method of controlling and operating an engine'which is also of my invention.A

It is understood that the embodiment of the invention described herein is only'one of the many embodiments my invention may take, and I do not wish to be limited in the practice of the invention, nor in my claims, to the particular embodiment set forth.

What Iclaim is 1. In an internal combustion engine, in comblnation, a power cylinder and piston, and a scavenging cylinder and piston therefor, arranged in tandem, means for controlling 'the admission of fuel charges to said p ower cylinder to drive the engine on fuel, and means operable by or independently of sa id last named means for controlling admission of compressed air to said scavenging cylmder to drive the engine by compressed air alone.

2. In an internal combustion engine, in comblnatlon, a powercylinder and piston, and a scavenging cylinder and piston therefor, arranged in tandem, means for controlllng theadmission of fuel charges tosaid power cyhnder to drive the engine on fuel,

means operable by or independently of said last named means for controlling admission der to drive the engine by compressed air alone, and means for connecting said last two means to operate to drive the engine on fuel and simultaneously by compressed air admitted to said scavenging cylinder.

3. In an internal combustion engine, in

combination,ra power cylinder and piston, and a scavenging cylinder and piston therefor, arranged in tandem, 'fuel controlling means for controlling the admission of fuel charges to said power cylinder to drive the engine on fuel, air controlling means operable by or independently of said fuel controlling means for controlling admission of compressed air to the scavenging cylinder, said air controlling means including an operating lever, and means for connecting the same to saidk fuel ycontrolling means to enable both said fuel controlling means and said air controlling means to be operated si,- multaneously by said fuel controlling means.

4. In an internal combustion engine, in combination, a power cylinder and piston and a scavening cylinder and piston therefor, arranged in tandem, fluid operated valve means controlling the flow of air from said scavenging cylinder to said power cylinder, means for controlling the admission of fuel to said power cylinder to drive the engine on fuel', and means driven by a moving part of the engine for controlling said valve to effect air admissionto said scavenging cylinder to drive the engine by compressed air lalone when the fuel is cut off.

5. In an internal combustion engine, in combination, a power cylinder and piston and ay scavenging cylinder and piston therefor, arranged in tandem, valve means controlling the iiow of air from said scavenging cylinder to said power= cylinder, means for controlling the admission of fuel to said power cylinder to drive the engine on fuel, and means for automatically controlling said valve by the admission of airto said scavenging cylinder to drive the engine by compressed air alone when the fuel is cut ofl".

6. In an internal combustion engine having a power cylinder and piston therefor, and an air cylinder and ,piston therefor, in combination, a .manually operated member, mechanism controlled by the first movement of said member for driving said engine with compressed air alone, means controlled" by the further movement of said member for driving said engine also by fuel admittedto said power cylinder and mechanism controlled by the further movement of said member for driving the* engine by means of fuel alone. f

7 In an internal combustion engine having a power cylinder and piston therefor, and an air cylinder land piston therefor, in

of compressed airfto said scavenging cylinv combination, a. manually operated member, mechanism cont-rolled by the first movement of said member for driv-ing said engine with compressed air alone, means controlled by the further movement of said member for driving said engine also by fuel admitted to said power cylinder, mechanism controlled by the further movement of said member for driving the engine by means of fuel alone, and automatic means for cutting off the supply of air to the air cylinder when said member receives said last named further movement.

8. ln an internal combustion engine having a power cylinder and piston therefor,

and an air cylinder and piston therefor, in

combination, a manually operated member, mechanism controlled by the first movement of said member for driving said engine in either direction with compressed air alone, means controlled by they further movement of said member for driving said engine also by fuel admitted to said power cylinder, and mechanism controlled by the further movement of said member for driving the engine by means of fuel alone.

ln an internal combustion engine having a power cylinder` and a piston therefor and an air cylinder and piston therefor, in combination. a manually operated member, an air controlling member actuated by the first movement of said manually operated member, means controlled thereby for admitting air to the air cylinder to drive the engine with compressed air alone, means controlled by the further movement of said manually operated member for driving the engine by fuel admitted 'to said power cylinder, said air controlling member being arranged to bereleased from said manually operated member.

10. In an internal combustion engine yhaving a power cylinder and a piston therefor and an air cylinder and piston therefor, in combination. a manually operated member, an air controlling member actuated by the first movement of said manually operated member, means controlled thereby for admitting air to the air cylinder to drive the engine in yeither direction with compressed ai alone, means controlled by the further movement of said manually operated member for driving the engine by fuel admitted to said power cylinder. said air controlling member being arranged to be released from said manually operated member, and .means for preventing a reverse movement of said air-controlling member when the engine is running on fuel.

11. ln an internal combustion engine having a power cylinder and a piston therefor and an air cylinder and a piston therefor, in combination, a manually operated member, an actuator arranged to be moved thereby. an air controlling member in the path of movement of said actuator, means controlled by said air controlling member for admitting air to the air cylinder to drive the engine with compressed air, means controlled by the further movement of said manually operated member for driving the engine by fuel admitted to said power cylinder, said air-controlling member being arranged to move out of the path of movement of said actuator and thereby become released therefrom, and means for actuating the same to cut ofi' the supply of air to said air cylinder.

l2. In an internal combustion engine having a power cylinder and a 'piston therefor and an air cylinder and a piston therefor, in combination, a manually operated member, an actuator arranged to be moved thereby, an air controlling member in the path of movement of said actuator, means controlled by said air controlling member for admit-` ting air to the air cylinder to drive theengine in either direction with compressed air, means controlled by the further movement of said manually operated member for driving the engine by fuel admitted to said power cylinder, said air-controlling member being arranged to vmove out of the path of movement of said actuator and thereby become releasedtherefrom, means for actuating the same to cut ofi' the supply of air to said air cylinder, and means for preventing an independent reverse movement of said air-controlling member when the engine is running on fuel.

13. In an internal combustion engine having a power cylinder and a piston therefor and an air cylinder and a piston therefor, in combination, a manually operated member, an actuator arranged tobe moved thereby, an air controlling member in the path of movement of said actuator, means controlled by said air controlling member 'for admitting air to the air cylinder to drive the engine in either direction with compressed air, means Acontrolled by the further movement of said manually operated member for driving the engine by fuel admitted to said power cylinder, said air-controlling member being arranged to move out of the path of movement of said actuator and thereby become released therefrom, and means for actuating the same to cut ofl" the supply of air to said air cylinder, said actuator having a part for obstructing an `independent reverse movement of said air-controlling member when the. engine -is running on fuel.

14. In an internal combustion engine having a power cylinder and a piston therefor and an air cylinder and a piston therefor, a hand operated member, mechanism actuated by the first movement of said hand operated member for admitting air to the said air cylinder to drive the engine in either direction with air, means actuated by the further movement of said hand operated member for admitting fuel to the power cylinder to drive the engine with fuel, and automatic means for preventing afurther admission of air to the air cylinder in a way to oppose rotation of the engine in the driving direction.l

15. In an internal combustion engine having a power cylinder and a piston therefor and an air cylinder and a piston therefor,

a hand operated member, an air-controlling member normally in a neutral position, an actuator arranged to be moved by said hand operated member for actuating said air controlling member, means controlled by said air-controlling member for admitting air to the air-cylinder to drive the engine in either direction, said air-controlling member being arranged to release itself automatically from said actuator, means controlled by the further movement of said hand operated member for driving the engine by fuel admitted to said power cylinder, said hand operated member and said actuator having a connection permitting said further movement of said hand operated member without imparting substantial movement to said actuator, said actuator having a part obstructing a movement'of said air-controlling member beyond the said neutral position thereof to prevent independent movement of said air-controlling member in a direction tending to rotate the engine oppositely to the driving direction.

16. In an internal combustion engine having a power cylinder and a piston therefor and an air cylinder and a piston therefor, the combination of a hand operated member, an air-controlling member arranged to be actuated b'y the first movement of said hand operated member, means controlled by said air-controlling member for admitting air to the air cylinder to drive the engine by air alone, means for admitting fuel to said power cylinder actuated by said hand operated member and arranged to drive the engine simultaneously with fuel and by air, automatic means forcutting olf the air supply to` the air cylinder during the continued movement of the hand operated member in the same direction, and. means forgiving an increased fuel supply to the power cylinder by said continued movement of said hand operated member.

17. In an internal combustion engine havmg a power cylinder/and a piston therefor and an air cylinder and a piston therefor,

- the combination of a hand operated member, an air-controlling member arranged to be actuated by the first movement of said hand operated member, means controlled by said air-controllin member for admitting air to the air cyhnder to drive the engine in either direction by air alone, means for admitting fuelr to said power cylinder actuated by said hand operated member and arranged to drive the enginesimultaneously with fuel and by air, automatic means for cutting off the air supply to the air cylinder during the continued movement of the hand operated member in the same direction, means for giving an increased fuel supply to the -power vcylinder by said continued movement of said hand operated member, and means for preventing an independent movement of said air-controlling member in a direction tending to rotate the engine opppsitely to the direction in which the engine is running.

18. In an internal combustion engine, in combination, a power cylinder and piston and an air cylinder and piston, a hand operated memberfor controlling the admission of explosive charges to said power cylinder to drive the engine on fuel, an actuator 4adapted to be moved by said hand operated member, means controlled thereby for admitting air to the air cylinder to drive the engine by air at the same time that it is driven by the fuel in the power cylinder, and automatic means for cutting off the admission of air when said actuator hasy arrived at a predetermined point.

19. In an internal combustion engine, in combination, a power cylinder and piston and an air cylinder and piston, an air-conf trolling member,l and means controlled f thereby to start the engine in'either direction with `com ressed air, hand-operated means for admitting fuel to the power cyl-` inder for driving the engine by fuel while it is being driven on air and including engaging means for engaging said air-controllingmember arranged to move said air-controlling member in either direction, said last means being arranged to release said aircontrolling member and shut off the air at a predetermined point.

21. In an internal combustion engine, in combination, a power cylinder and piston and an air cylinder and piston, an: air-controlling member, and means controlled thereby to start the engine ineither direction with compressed air, hand-operated means for admitting fuel to the power cylinder for driving the engine by fuel while it is being driven on air and including engaging means consisting of spring pressed dogs for engaging opposite sides of said4 air-controlling member arranged to move said aircontroiling member' in either direction;

22. In an internal combustion engine, in combination, a power cylinder and piston and an air cylinder and piston, hand-operated means for controlling the driving of the engine by fuel admitted to said power cylinder', an actuator adapted to be moved thereby, said actuator having a movable dog, an air-controlling member for controlling the driving of the engine by admitting compressed air to said air cylinder, said aircontrolling member lying in the path of said dog when said actuator' moves, said dog being arranged to release said air-controlling memberl after a predetermined movement of said actuator, means for returning said aircontrolling` member to its oit position, said dog being yieldingly mounted so as to permit the same to pass said air-controlling member upon the return movement of said actuator.

i225. In an internal combustion engine, in combination, a power cylinder and piston and an air cylinder and piston, hand operated means for controlling the driving of the engine with fuel admitted to the power cylinder including a movable actuator, said actuatorI having a pair of spring pressed dogs, and an air-controlling member disposed between said dogs and adapted to be displaced by the movement of said actuator in either direction, means controlled by said air-controlling memberfor driving the engine with compressed air admitted to said air cylinder', said actuator having suilicient movement to release said air-controlling member at'tcr a predetermined point in the movement ot' said actuator, said air-'controlling member having a neutral point in which no air will be admitted to the air cylinder, means for returning said air-controlling member to said neutral point, said dogs being arranged to yieldingly engage said aircontrolling member upon the return movement ot' said actuator and move aside to permit said actuator to come into its neutral position with said air-controlling member disposed between said dogs.

24. In an `internal combustion engine, in

combination, a power cylinder' and piston movement to release said air-controlling member after a predetermined point in the movement of said actuator, said air-controlling member having a neutral point in which no air will be admitted to the air cylinder, means for returning said air-controlling member to said neutral point, Said dogs being arranged to yieldingly engage said air-controlling member upon the return movement of said actuator and move aside to permit said actuator' to come into its neutral position with said air-controlling member' disposed between said dogs, said actuator' having a part in the path of movement of said air-controlling member to prevent a reverse movement of said air-controlling member independently of said actuator beyond the neutral point of said air-controlling member.

25. ln an internal combustion engine, in combination a power cylinder and piston, and an air cylinder' and piston, a hand wheel for controlling the driving of the engine with fuel admitted to lsaid power cylinder, an actuator adapted to be moved by said wheel, 'a pair ot' dogs mounted on said actuator, an air-controlling lever for' controlling the driving ot the engine by compressed air admitted toV said air cylinder', said aircontrolling lever having a neutral position lying between said dogs when the engine is still, said actuator dogs being arranged to move said lever in either direction andrelease said lever after a predetermined move` ment of said actuator, means for returning said air-controlling lever to its neutral position after its release, said dogs being arranged to yield upon engagement with said lever in the return movement of said actuator and move aside to permit said actuator to come into position with said lever lying between said dogs. Y

26. In an internal combustion engine, in combination, a. power' cylinder and piston and an air cylinder and piston, a hand wheel for controlling the driving of the engine by admitting fuel to said power cylinder, an actuator' in the form ot a slide adapted to be moved by said hand wheel, a pair ot' spring pressed dogscarriedby said actuator, an air controlling lever adapted to swing in either direction, means controlled thereby for driving `the engine in either di rection by compressed air admitted to said air cylinder, said lever having .a neutral position lying between said dogs and arranged to be moved in either direction by one or the other of said dogs, said actuator having a movement in either direction su# icient to release said lever from either of said dogs, and means for returning said lever to its neutral position when the same is released, said dogs being arranged to yieldingly engage said lever upon the re- 

